code: def check_forward(self, x_data):
      x = chainer.Variable(x_data)
      with self.assertRaises(ImportError):
          self.func(x)
  
file_path: chainer/tests/chainer_tests/functions_tests/math_tests/test_lgamma.py
imports: import unittest
  import numpy
  import chainer
  from chainer import backend
  from chainer.backends import cuda
  import chainer.functions
  from chainer import testing
label_desc: Use image node_id 2 for calling the TestLGammaExceptions obj's underlying member method code with example usage: obj.check_forward(x_data) without return types